<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.bundle.min.js"></script> </head>

<body>
    <div class="btn-group btn-group-vertical" role="group" aria-label="Vertical Btn">
        <button type="button" class="btn btn-secondary mt-1">Top</button>
        <button type="button" class="btn btn-secondary mt-1">Middle</button>
        <button type="button" class="btn btn-secondary mt-1">Bottom</button>
    </div>
</body>

</html>